Operating gear for tuning elements



1951 H. E. OVERACKER 2,570,703

OPERATING GEAR FOR TUNING ELEMENTS Fild Jan. 21, 1950 INVEN TOR. Horace E. Overacker Patented Oct. 9, 1951 OPERATINGVG'EAR FOR TUNING ELEMENTS Horace E. Overackr, Los Altos, Califl, assi n to Hewlett-Packard Company, Palo Alto,-. Calif., acorporation of California Application January 21, 1950, Serial No.13a905 4.0laims. (o1. 74%:1385).

This invention relates generally to drive means for adjusting the angular setting of rotary instruments shafts, particularly electrical instruments such as are employed as component parts of radio signaling or other types of electric equipment I In many types of radio signaling equipment it is desirable to provide gang operating means for changing the setting of two or more instrument shafts. In addition it is frequently desirable to effect individual adjustment of one instrument shaft, without disrupting the gang operating means.

It is an object of the present invention to provide improved means capable of effecting both conjoint and individual instrument shaft control, and which is characterized particularly by relatively simple mechanical construction and ease of operation.

It is another object of the invention to provide improved drive means of the above character which incorporates provision for preventing backlash between the operating elements employed. 1 I Additional objects and features of the invention will appear from the following description in which the preferred embodiment has been set forth in detail in conjunction with the accompanying drawing.

Referring to the drawing- Figure 1 is a cross-sectional view taken alon the line ll of Figure 2, and illustrating one embodiment of the invention.

Figure 2 is a sectional view takenalong the line 2 -2 of Figure 1. r

Figure 3 is a cross-sectional detail taken along the line 3-3 of Figure 2.

The preferred form of the invention illustrated in the drawing consists of two aligned shaft sections, Illa and Illb, which are carried by the journals II and I2 on the chassis or fixed support l3. A coupling sleeve I6 is fixed to shaft section l c z as by means of pin I1, and is splined to the adjacent end of shaft section lb. The splined connection can consist. of a pin H! which extends through the shaft section lllb, and which has slide blocks I9 attached to its ends. The sleeve [6 has slots 2| which serve to accommodate theblocks IS. The splined connection 'enables the shaft section lflb to move axially relative to section Ifia, for a purpose to be presently explained. r

The ;two instruments which are to be operated, such as variable condensers (not shown) or the like are assumed to have rotatab e adjusting shafts 22 and 2a. Both ofthese shafts extend at right-angles-to the axis of the shaft sections Illa and lb. Drive gearingserves to operatively connect each instrument shaft with its corresponding shaft section. Thus shaft section Illav carries a worm 24, which engages the teeth of worm gear 26. Shaft section Iilb similarly caries a worm 21, which engages the teeth of the worm gear 28. The'two worm gears 26 and 28 are fixed-to the-instrument shafts 22 and 23.

The shaft section Illa is shown extending through an instrument panel 29, where it is provided with a manually operated control knob 3|,

Upon turning the knob 3| to turn theshaft sections l3a and lflb, the instrument shafts .22 and 23 will be turned in unison. V

Individual rotation of the instrument shaft 23 without turning shaft 22, is effected by means which is manually operated to shift. the shaft section lilb axially. ,It will beevident that such shifting movement results in axial movement of the worm 21, whereby the gear 28 and shaft 23 are turned a limited angular amount. The means provided for axially shifting shaft sec tion Iilb includes a collar 32 which is fixed to shaft section lflb, and which is engaged by the lower extension of the lever 33. Lever 33 is formed of two parts, whereby its lower end' portion forms in effect a fork for embracing the op posite sides of collar 32. The lower end of each lever part is bifurcated at 35, to accommodate the rim of the collar. Th'upper portion of lever 33 is pivoted at 34 to support l3 and at 31' to a member 38. A rotatable rod 39 has its one end portion 4| threaded to engage a threaded bore.

formed in member 38. Shaft 39 is journaled to the chassis, and likewise extends through the instrument panel 29, where it is provided with the control knob 42. Turning of the knob 42 causes the member 38 to advance or retract relative to rod 39, thereby rocking the lever 33.

In conjunction with the apparatus described above, it is desirable to provide means to prevent backlash between the working parts. Thus the drums 43 and 44 are mounted upon the instrument shafts 22 and 23, and these drums are engaged by the end portions of the coil spring; 46. It will be noted that each end portions of the spring is wrapped around its associated drum;

and one end of the spring is anchored to drum 43 at 41, and'the other end anchored to drum 44 at 48. With the spring 46 under tension, and with the end portions wrapped about the drums 43 and 44 in the manner shown in Figure 2, the spring serves to apply clockwise torque to the shaft section I 0a.

shaft 22, and counterclockwise torque to shaft 23. The amount of torque thus provided serves to take up backlash between the worms and the worm gears, between the collar 32 and lever 33, and also between this lever and the shaft 39. Thus backlash is eliminated both for conjoint rotation of the shafts 22 and 23 in response to turning the knob, 3|, and also for individual rotation of the shaft 23 responsive to turning the control knob 42.

Operation of the apparatus described above can be summarized as follows: Normally the shaft sections Illa and lb are held in fixed axial relationship to each other; Upon turningknob 3| both shaft sections Illa and lb rotate in unison, and similar rotation of the Worms 2'4' and 21 serves to rotate the, gears. 26 and 28, to-- gether with the shafts 22 and 23, in unison. R0,-

tation of the knob 42 serves to rock the lever 33' to shift the shaft section lllb axially relatively to This causes axial movement of the worm 27, with the result that the gear 28 and the instrument shaft 23 are individually rotated. Afterindividually rotating theshaft 23, rotation of the knob 3| for gang control willserve to maintain the new angular relationship between theshafts 22 and 23-;

' It will be. evident from the foregoing that I have provided a novel drive means applicable to various types of equipment where it is 'desired to adjust two or more instruments conjo'intly, or adjust one. ofthem individually.

Backlash is eliminated from all of the working parts, whereby the instruments can be adjusted to a high degree of accuracy.

' Although the apparatus as described above and. illustrated in the drawing is particularly adapted for adjusting the-shafts of only two instruments, it. will be-evident that the principles of the invention can be applied to more than two instruments.

Although. the wormsand worm gears illus trated are intended to turn the shaft 22and 23 equal angular amounts for a given amount of rotation of shaft section" Illa, it will be evident that insome instances it may be desirable to modify the. driveratio between a shaft section and" its associated instrument shaft. This, can b'eaccomplished by introducing additional gear elements, or by changing the sizes of the worm and worm gear elements.

I claim:

1. Drive means for adjusting the angular set-- ting'of the rotary operating shafts of two instruments, comprising. twoaligned-shaft sections,

means for journalingsaid shaft sections, a splined: coupling between said shaft sections whereby said sections rotate ineuniso'n. and one section can be moved axially relative to: thecther, a manual operating memberattached" to one shaft section for; manually rotating both said sections, drive gearing: operatively; connecting each shaft section with an associated instrument shaft, each drive gearing; including a worm mounted upona shaft section and a worm'gear engaged by said worm, and -meansfor effecting, axial movement of the other shaftsection'with respect to said'one shaft sectionto'thereby cause individual rotation of one instrumentshaft said; last means comprising; a. manually; operated member, and meansconnecting said manually operated memberto said other- --shaf.t:-section to, effect axial movement ofsaid other shaft section upon, mov s id ma ally neretedmember.

2. Drive means as in claim 1 in which said means for effecting axial movement of said other shaft section comprises a collar mounted upon said other shaft section, a fulcrumed lever having one end of the same operatively connected to said collar to shift the same in an axial direction responsive to rocking of the lever, a manually operated, rotatable 'member, and means operative'ly connecting said last member with said lever to cause rocking of said lever responsive to rotation of said member.

3; Driving means for adjusting the angular setting of the rotary operating shafts of two instruments, comprising a pair of aligned shaft sections, means forming a splined connection tion-with an associated instrumentshait for simultaneous rotation of the instrument shafts when the haft sections'are rotated manually, each drive gearing including aworm mounted upon the shaft sect'ien'and a worm gear engaging said worm and rotatable about an axis at right angles to the axis of the shaft sections, means for continuously applying oppositely di= rected' torques to said" Worm gears to prevent backlash, and means for shifting theothershaft section'with' respect to said one shaftsec'tion to effect individual adjustment of one instrument shaft relative to the other.

4, Drive means for adjusting the angular setting ofthe rotary operating shafts of' two" instruments, comprising a" pair of aligned shaft; sections; couplingmeans serving to form a splined connection betv've'e'n said shafts whereby the two shafts are caused to rotate'i'nimisonand one shaft can n'iove axially relative to the other shaft, means serving to-journalsaidshaft sections, a manuallyoperatedmemberattached to one shaft secticnf'or rotating both saidsections, worm gear attached to the instrument shafts", the-instrument shafts extending at rightangles to the shaft section, worms attached to the shaft sections and operatively engaging worm gears, drums mounted upon: theinstrument shafts; a tension spring having its end portions-associated with said drums, each-end portion'of the spring being wrapped about an associated drum endanchored thereto, whereby said" tension' spring ap plies torque in o posite directions to said iiistrument shafts, a collar mounted upon said other shaft section, a lever having one'end' of the same'engaging said'bo'llar whereby when said lever is rocked said other shaft section is moved longitudinally, a:.manual l y: rotatable rod, and means: operative'lyconnectiiigsaidlast named rod -w-itl'1- said: leverto. causeirocki ng' of said lever when saidrod-is rotated.

HORACE E. OVER'ACKE RH.

REFERENCES CITED The followingreferences are=of record in. the

file of this patent:

UNITED STATES PATENTS.

Number Name new 1,660,368 Asbury Feb; 28, 1928 FOREIGN PATENTS Number W Country Date 

